1. Field of the Invention
This invention relates to a method and apparatus for supporting and tensioning a fabric, and more particularly to an expandable frame assembly for supporting and stretching canvas and the like.
2. Description of the Related Art
Conventional stretchers are generally in the form of a wooden frame onto which a piece of canvas or other material is secured by staples or tacks. Wedges are forced into the corners of the wooden frame to vary the spacing between the frame portions such that the material supported thereon is tautly stretched in all directions.
Other types of canvas stretching frames are also known. An example of an early canvas stretching frame is disclosed in U.S. Pat. No. 1,916,023 to A. E. Shull which employs a series of threaded coupling elements mounted on threaded bolt members. Rotation of the coupling elements serves to spread the frame portions to stretch the canvas supported thereon. A later canvas stretching frame disclosed in U.S. Pat. No. 4,301,853 to Vidal includes a plurality of threaded tensioning rods which are each biased by a compression spring. The tensioning rods can be adjusted to vary the dimensions of the frame. Another canvas stretching frame disclosed in U.S. Pat. No. 4,549,596 to Staro includes inserts which form angles at the corners of the frame. Slide blocks are provided on the frame with adjustable tensioning screws for exerting a force against the frame to stretch the canvas supported thereon.
Other types of expandable frames are also known in the art which are particularly configured to support a fabric mesh for use during a silk screening operation. Such prior art stretching frames are disclosed, for example, in U.S. Pat. Nos. 5,076,162 to Goin; 5,113,611 to Rosson; and 5,271,171 to Smith.
It would be beneficial to provide a stretching frame which includes a simple mechanism for adjusting the relative positions of the frame portions and which is readily adaptable to support and tension either canvas or silk screening material.